The present invention relates to an audio mixing device that mixes a plurality of digital audio signals, performs digital-to-analog conversion (hereinafter, referred to as D/A conversion), and outputs an analog audio signal, a method thereof, and an electronic device including the audio mixing device.
Japanese Patent application publication number 2007-142996 discloses an audio mixing device that mixes digital audio data, performs D/A conversion, and outputs an analog audio signal.
In the present specification, audio data or an audio signal refers to low-frequency data and/or a signal including sound and/or music.
FIG. 5 is a block diagram illustrating a constitution of an audio mixing device according to a conventional technique. In FIG. 5, PDM (Pulse Density Modulation) signal generators 1, 2, 3 generate PDM signals P1, P2, P3, respectively, by performing delta-sigma modulation (Δ-Σ modulation) on inputted digital audio signals S1, S2, S3, respectively, and output the PDM signals P1, P2, P3 to D/A converters 11, 12, 13, respectively. The D/A converters 11, 12, 13 perform D/A conversion on the inputted PDM signals P1, P2, P3, respectively, and output analog audio signals A1, A2, A3 to an adder 14. The adder 14 adds the three inputted analog audio signals A1, A2, A3 and outputs an analog audio signal A10 which is a signal in which the three inputted analog audio signals A1, A2, A3 have been mixed.